I’m running a PBS instance (plus networking containers) for 4years now, cc on file for the first 2 years, now on file, but my usecase is operating within the free-forever tier.
My instance has not been deleted by them, though I’ve rebuilt the multiple times since.
The region you are on might be struggling with capacity issues, I use middle east region and never encountered account/vm deletions (yet). For my case, latency isnt an issue so i dont mind having it ona far away region.